Normal heart rhythm is initiated and regulated by an intracellular calcium clock within pacemaker cells

VA Maltsev, EG Lakatta - Heart, Lung and Circulation, 2007 - Elsevier
For almost half a century it has been thought that the heart rhythm originates on the surface
membrane of the cardiac pacemaker cells and is driven by voltage-gated ion channels
(membrane clocks). Data from several recent studies, however, conclusively show that the
rhythm is initiated, sustained, and regulated by oscillatory Ca2+ releases (Ca2+ clock) from
the sarcoplasmic reticulum, a major Ca2+ store within sinoatrial node cells, the primary
heart's pacemakers. Activation of the local oscillatory Ca2+ releases is independent of …